Soldering irons featuring replaceable tips are well known. A variety of tip configurations is desirable for different uses in the constantly evolving electronics industry. Replaceable tips afford greater flexibility to the user since, a tip, upon cooling, may be substituted for an alternative tip having a different geometric configuration permitting the user to work into tight regions, flat surfaces, etc.
Some problems associated with replacing tips in conventional soldering irons are notable. First, the time lag between operations is considerable; several minutes being required to cool a tip, replace it with another and heat the substitute tip; a major production inefficiency. Heat transfer from the tip/heater interface into the handle generally mandates the handle be separated by several inches from the tip in order to provide sufficient insulation therebetween. Additional problems result from corrosion which often freezes the tip in the handle or freezes the screw holding the tip. Such corrosion can be attributed to high temperatures at the interconnection between the tip and heater. Once such corrosion set in, the iron must be discarded since the tip cannot be extracted without destroying the iron.
Metallurgical based temperature autoregulation has been applied to soldering irons, see U.S. Pat. No. 4,256,945 and application Ser. No. 666,346 filed Oct. 30, 1984 now U.S. Pat. No. 4,745,264. Such autoregulation eliminates the need for external sensing and adjustment features. Temperature autoregulation restricts the tip operating temperature to a defined temperature and which facilitates precision soldering operations as well as minimizing thermal damage to the soldering iron and maximizing tip life. Thus, temperature autoregulating soldering irons are preferred to their conventional counterparts.
Nowhere has been found, however, a cartridge tip soldering iron which incorporates temperature autoregulation. Furthermore, a cartridge soldering iron permitting almost instantaneous exchange of tips has not been found. Lastly, conventional soldering iron design does not incorporate a structure for minimizing heat transfer between the tip and the handle, thereby permitting maximum tactile manipulation.